Articulated external orthopedic fixation system and method of use

ABSTRACT

An external fixation system (10) comprising one or more rings (14), elongated members (16), extension fingers (18) with pin holders (52), wire holders (22), clamping assemblies (20), screws (24) or wire (26) for securing parts of a bone (12), and rod connectors (174). The extension fingers (18) are positioned axially and radially along the elongated members (16). The pin holders (52) move axially along and radially around the extension fingers (18), and are secured in place using a one-hand operation which also secures the screw (24) in place. The screws (24) are secured to the pin holders (52) from a point which may be positioned and oriented with full spatial articulation in three dimensions. The rings (14) are provided with openings (104) composed of intersecting apertures (106) to decrease the spacing between available locations. A lengthening-compression-distraction (LCD) bar (28) permits traction or compressive forces to be exerted on the bone (12), as well as dynamization for weight-bearing compression. Certain components of the LCD bar (28) can be reconfigured during fabrication to facilitate use in a transport mode. The rod connector (174) joins two elongated members 16 at a selected and adjustable angle, and includes two open-ended U-collars (176, 178) stacked on a shaft (182) for rotation until the U-collars (176, 178) are compressed to clamp the elongated members (16).

This is a Divisional of co-pending Parent application Ser. No.08/717,224, filed Sep. 26, 1996.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to external fixation systemsused for securing separated or fractured segments of a bone in properposition, alignment, and orientation for healing or therapeuticmanipulation.

2. Scope of the Prior Art

A wide variety of external fixation or wire tensioning systems are knownto the orthopedic field. Two popular types are the "ring-and-rod" andthe "jointed bar" systems, and several variations or hybrids based uponthese two basic types are known. The "ring-and-rod" systems arecharacterized by longitudinal bars having pin-holding clamps which canbe secured in different positions and angular configurations relative tothe parts of a fractured bone requiring fixation. The longitudinal barsmay optionally be mounted on one or more partial rings whichcircumscribe the bone. In contrast, the "jointed bar" systems arecomposed of several rigid segments coupled by various types of jointswhich may be locked in a desired configuration.

Jointed bar systems generally display the advantage of providing agreater range or degree of non-uniform articulation, but inherentlypresent a significantly larger profile and greater complexity inpositively securing the segments and joints in the desiredconfiguration. Ring-and-rod systems may provide greater stability and alower lateral profile with the ability to employ both screw fixation andwire tensioning, however their range of articulation is generally morelimited and the available locations for positioning the screws and wirerelative to the corresponding rods or rings may be insufficient (or lessthan desirable) for some applications.

Among systems utilizing rings, there is a further distinction between"through-the-ring" systems and "outrigger" systems. In through-the-ringsystems, the main longitudinal rods, bars, and wire or pin holdersextend through apertures in the ring itself and are secured in positionby fasteners or clamps. In "outrigger" systems, the rods are connectedto the rings by clamps which ride along the peripheral edge or rim ofthe ring. The outrigger systems can provide continuous adjustability inthe position of the rods along the rings, but lack the stability andusually present a larger lateral profile than through-the-ring systems.

Several representative examples of commercially-available externalfixation systems which exemplify the "ring and rod" and "jointed bar"systems and their hybrids or variations are disclosed in the papersaccompanying this specification, and are incorporated herein byreference as though fully set forth and described in detail, along withthe additional patents and prior art references made of record.

SUMMARY OF THE INVENTION

The external orthopedic fixation system of this invention provides theoperator with the advantages of the increased stability, full spatialarticulation, and lower lateral profiles than previous ring-and-rod orjointed bar systems. In addition, the components of the system may bemore readily positioned and secured to provide optimal placement andorientation of the pins, screws, or tensioning wires for the desiredeffect in the given application.

Briefly described, the external fixation system includes extensionfingers which may be positioned both axially and radially along anelongated rod member, and pin holders which may be moved axially alongand radially around the extension fingers. The extension fingers and pinholders may each be clamped and secured in a desired position using aone-hand operation. The point at which the screws or wire are mounted onthe pin holders may be positioned and oriented with full spatialarticulation in three dimensions. The partial rings are provided withopenings to receive the elongated rod members (or wire holder members),with the openings composed of intersecting apertures to decrease thespacing between available locations for the elongated rod members orwire holders. One or more of the elongated rod members may constitute alengthening-compression-distraction (LCD) bar which permits longitudinalforces to be exerted on segments of the bone, or may be easily convertedto a dynamic mode allowing weight-bearing compression. The basiccomponents of the LCD bar can be reconfigured during fabrication tofacilitate use in a transport mode.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of one embodiment of each of thecomponents of the external fixation system of this invention shown in arepresentative example of their applied environment;

FIG. 2 is a side elevation view of one embodiment of the extensionfinger assembly of this invention;

FIG. 3 is a left end elevation view of the extension finger assembly ofFIG. 2;

FIG. 4 is a right end elevation view of the extension finger assembly ofFIG. 2;

FIG. 5 is a top view of the extension finger assembly of FIG. 2;

FIG. 6 is a bottom view of the extension finger assembly of FIG. 2;

FIG. 7 is an exploded perspective view of the extension finger assemblyof FIG. 2;

FIG. 8 is a detail view of the bottom surface of the clamp rod shown inFIG. 7;

FIG. 9 is a side cross section view of the bottom surface of the clamprod shown in FIG. 7 taken through line 9--9 in FIG. 8;

FIG. 10 is a partially broken away side cross section view of theextension finger assembly of FIG. 2 taken along the longitudinal axisthereof;

FIG. 10A is a side cross section detail view of the extension fingerassembly of FIG. 2 taken through line 10A--10A in FIG. 2;

FIG. 11 is a top plan view of an illustrative example of a ring memberof this invention;

FIG. 12 is a side cross section view of the ring member of FIG. 11 takenthrough line 12--12 in FIG. 11;

FIG. 13 is a rear perspective view of one embodiment of the clampingassembly of this invention;

FIG. 14 is a side elevation view of an orthopedic screw using with theexternal fixation system of this invention;

FIG. 15 is a detail view of the distal tip of the orthopedic screw ofFIG. 14;

FIG. 16 is a cross section view of the proximal end of the orthopedicscrew of FIG. 14 taken through line 16--16 in FIG. 14;

FIG. 17 is an end elevation view of the distal end of the orthopedicscrew of FIG. 14;

FIG. 18 is a side elevation view of one embodiment of thelengthening-compression-distraction (LCD) bar of this invention with aring member mounted at one end and an extension finger assembly at theopposing end;

FIG. 19 is a cross section view of the LCD bar of FIG. 18 taken throughline 19--19 in FIG. 18;

FIG. 20 is a diagrammatic depiction of the LCD bar of FIG. 18 showingthe sleeve members in their retracted position, and their extendedposition in phantom;

FIG. 21 is a diagrammatic depiction of a reconfigured embodiment of thecomponents of the LCD bar in the transport mode;

FIG. 22 is a side elevation view of the wire holder of FIG. 1;

FIG. 23 is a bottom view of the wire holder of FIG. 22;

FIG. 24 is a side cross section view of the wire holder of FIG. 22 takenthrough line 24--24 in FIG. 23;

FIG. 25 is a perspective view of a rod connector used with the externalfixation system of FIG. 1;

FIG. 26 is an exploded view of the rod connector of FIG. 25;

FIG. 27 is a side elevation view of the LCD bar with ring membersmounted at each opposing end;

FIG. 28 is a partially broken away cross section view of the LCD bar ofFIG. 27 taken through line 28--28 in FIG. 27;

FIG. 29 is an end view of the LCD bar received within a ring member andclamp;

FIG. 30 is a diagrammatic view of one exemplary embodiment of theexternal fixation system in a working environment with four extensionfinger members and pins fixing a bone; and

FIG. 31 is a diagrammatic view of one exemplary embodiment of theexternal fixation system in a working environment with two ring membersconnected by a pair of LCD bars, each with four wire holders fixing abone.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The external orthopedic fixation system and method of this invention areillustrated in FIGS. 1-31 and referenced generally therein by thenumeral 10. The apparatus, method, and inventive elements or componentsthereof are generally referred to interchangeably in this specificationas the fixation system 10 for convenience.

Referring particularly to FIG. 1, the fixation system 10 includesseveral components utilized to secure the proper position, alignment,and orientation of a bone 12 during healing or for therapeuticmanipulation, illustrative examples of those components being shown in arepresentative depiction of their applied environment wherein the bone12 is the tibia in the leg of a patient.

The components of the fixation system 10 generally include one or moreof the following: a ring member 14, an elongated rod 16, an extensionfinger assembly 18, a clamping assembly 20, a wire holder member 22,screws or pins 24, wire 26, and a lengthening-compression-distraction(LCD) bar 28 which may also be reconfigured for use in a transport modeas described in further detail below. It may be readily appreciated thatany number of each component 14-28 may be utilized as needed or desiredin a particular application, and that certain components 14-28 may beomitted entirely in particular applications.

Extension Finger Assembly (18)

Referring particularly to FIGS. 2-10, one embodiment of the extensionfinger assembly 18 and its constituent subcomponents are shown ingreater detail. The extension finger assembly 18 includes a generallyelongated body member 30 having a generally cylindrical sleeve section32 defining a longitudinal bore 34 extending therethrough. An openC-shaped semicircular engagement collar 36 is disposed at and extendsfixedly from one end of the sleeve section 32, the collar 36 and sleevesection 32 having generally parallel faces 38 defining an opening sizedto receive a portion of the elongated member 16 therethrough. The bore34 receives a push rod 40 in close sliding contact therein, the push rod40 having a length slightly less than that of the bore 34 of the sleevesection 32. The end of the push rod 40 disposed toward the collar 36extends from the bore 34 of the sleeve section 32 into the interiorregion encompassed by the collar 36 and defines a generally concave face42 having a diameter conforming to the surface of the elongated member16 received within the interior region of the collar 36. The opposingend of the push rod 40 abuttingly contacts the inner surface of asecuring member 44 threadedly engaged within the end of the sleevesection 32, the securing member 44 urging the concave surface 42 of thepush rod 40 into frictional engaging contact with the elongated member16 to mount and secure the body member 30 on the elongated member 16 ata selected position and in a desired orientation. An alignment pin 46 isreceived within an aperture 48 in the push rod 40, and extends radiallyoutward from the push rod 40 and is slidably received within an exposedchannel 50 extending longitudinally along the sleeve section 32 tomaintain the concave face 42 of the push rod 40 in the properorientation and alignment for engaging the surface of the elongatedmember 16, and to prevent the push rod 40 from rotating and obstructingthe interior region of the collar 36.

A pin holder assembly 52 is mounted on the body member 30 so as to slideaxially along the exterior surface of the sleeve section 32 and rotatecompletely around the sleeve section 32. The pin holder assembly 52includes an eye-bolt or body member 54 having an enclosed collar 56 atone end, the collar defining a bore 58 sized to slidably receive thesleeve section 32 therethrough in close frictional contact. The opposingend of the body member 54 is threaded to receive a securing member 60thereon, the securing member 60 defining a central aperture 62 extendingtherethrough. The body member 54 similarly defines a hollow bore 64 intowhich a clamp member 66 is received, followed in linear sequence by afirst compression spring 68, clamp rod 70, second compression spring 72,and stem 74. The bottom face 76 of the clamp member 66 is generallyconcave, having a diameter conforming to the exterior surface of thesleeve section 32. The top face 78 of the clamp member 66 defines amultiplicity of radial serrations or teeth which mesh or mate with asimilar multiplicity of radial serrations or teeth defined by the bottomface 80 of the clamp rod 70. The first compression spring 68 is receivedwithin a closed bore 82 extending into the top face 78 of the clampmember 66, to contact and exert pressure biasing the clamp rod 70 andclamp member 66 away from one another. The serrations are sufficientlyshallow or beveled so that the clamp rod 70 and clamp member 66 mayrotate relative to one another through a continuous series of indexingpositions when the clamp rod 70 and clamp member 66 lightly orincidentally contact one another, but engage and secure the clamp rod 70and clamp member 66 relative to one another against rotation when theforce exerted on the clamp rod 70 by the second compression spring 72and stem 74 exceed the spring force of the first compression spring 68and the clamp rod 70 and clamp member 66 are pressed into engagingcontact. The second compression spring 72 is received on a top barrelportion 84 of the clamp rod 70, and the top barrel portion 84 of theclamp rod 70 is received within a bore 86 defined by the stem 74. Thetop portion of the stem 74 extends through the aperture 62 in thesecuring member 60, and defines a pin-receiving bore 88 extendingtherethrough and having a longitudinal axis aligned generally parallelwith that of the sleeve section 32. The lower radial flange 90 of theclamp rod 70 defines an upwardly-extending projection 92 which isreceived within a mating slot or groove 94 defined by the wall of thestem 74, such that the stem 74 will not rotate relative to the clamp rod70 at any time, and will not rotate relative to the clamp member 66 orsleeve section 32 of the elongated body member 30 when the serrations orteeth of the clamp rod 70 are pressed into engaging contact with thoseof the clamp member 66. The bore 86 in the stem 74 which receives thebarrel portion 84 of the clamp rod 70 communicates with thepin-receiving bore 88 extending through the stem 74 so that the top endof the barrel portion 84 of the clamp rod 70 extends into thepin-receiving bore 88.

The pin holder assembly 52 is fabricated and mounted on the sleevesection 32 over the threaded end thereof prior to the securing member 44being attached to the sleeve section 32. The pin holder assembly 52 isthen assembled with the securing member 60 being threaded onto the bodymember 54, and one or a pair of clinch tabs 96 are bent inwardly toengage under the radial flange 98 disposed beneath the threaded regionto prevent removal of the securing member 60 from the body member 54,yet permit the securing member 60 to be rotated relative to the bodymember 54 along the threaded region to tighten and loosen the clampingpressure exerted sequentially against the stem member 74, clamp rod 70,clamp member 66, and sleeve section 32.

The clamp member 66 further defines an aperture 196 receiving analignment and stopping pin 198 extending laterally therefrom. The pin198 is slidably received within a slot 100 defined by the threaded neckregion of the pin holder assembly 52, to thereby retain the concave face76 of the clamp member 66 in proper orientation and prevent the clampmember 66 from dropping out of the pin holder assembly 52 into the bore58 when the sleeve 32 is not present.

It may be readily appreciated that the extension finger assembly 18 maybe mounted on an elongated member 16 and moved to a desired position andorientation, with the securing member 44 being rotated to apply pressureon the push rod 40 and urge the concave face 42 of the push rod 40 intocontact with the elongated member 16. The securing member 44 is furthertightened to clamp or secure the body member 30 at that desired positionand orientation to prevent the body member 30 from sliding or rotatingrelative to the elongated member 16, or the securing member 44 may beloosened slightly to selectively permit such axial or rotationaladjustment of the body member 30 relative to the elongated member 16.

Similarly, when a pin or screw 24 is received within the pin-receivingbore 88 of the stem 74, the screw 24 and stem 74 may rotatesubstantially freely with the screw 24 being maintained in a planegenerally parallel to the plane of the longitudinal axis of the sleevesection 32. When the securing member 60 is initially tightened on thebody member 54, the clamp rod 70 will be urged into slight contact withthe clamp member 66 and opposed by the force of the first compressionspring 68, thus permitting the stem 74 and screw 24 to rotate in anindexing manner relative to the sleeve section 32 and clamp member 66,causing the pin holder assembly 52 to emit an audible clicking orratcheting noise. When the securing member 60 is further tightened ontothe body member 54, the clamp member 66 is urged into engaging contactwith the sleeve section 32 to securely fasten the sleeve section 32between the clamp member 66 and opposed confronting surface of thecollar 56. The serrated or toothed faces 78, 80 of the clamp rod 70 andclamp member 66 are pressed into engaging contact with one another, andthe top surface 102 of the clamp rod 70 is urged into engaging contactwith the screw 24 to securely fasten the screw 24 between the topsurface of the clamp rod 70 and the opposed confronting surface of thestem 74. Thus, tightening the securing member 60 simultaneously preventsthe pin holder assembly 52 from sliding axially or rotating relative tothe elongated body member 30, prevents the stem 74 and screw 24 fromrotating relative to both the pin holder assembly 52 and the elongatedbody member 30, and prevents the screw 24 from sliding axially withinthe bore 88 relative to the stem 74 and the pin holder assembly 52.

Ring Member (14)

Referring particularly to FIGS. 11 and 12, an illustrative embodiment ofa ring member 14 and corresponding clamping assembly 20 are shown ingreater detail. As shown in FIG. 11, the ring member 14 is an integralsemicircular open torpid having an inner, central, and outer diameters,a radial thickness, and which circumscribes an arc between the radiusedfree ends thereof. The ring member has a uniform thickness as shown inFIG. 12. The ring member 14 defines four openings 104, each composed ofa plurality of intersecting apertures 106 or placeholders through whichan elongated member 16 may be slidably received.

In one preferred embodiment of the ring member 14, the inner diameter is6.300", the central diameter is 7.111", the radial thickness is 0.812",the outer diameter is 7.112", and the thickness is 0.625". The ringmember 14 extends through an arc of approximately 280 °. In that firstembodiment, the two openings 104 adjacent to the free ends each containtwelve apertures or placeholders, and the two intermediate openings 104each contain eleven apertures or placeholders, for a total of forty-sixapertures 106 defining four openings 104. Each aperture 106 has adiameter of approximately 0.500", and the centerpoints of adjacentapertures 106 in each opening 104 are spaced apart approximately 5°.Each opening 104 is spaced apart 12° from the adjacent openings 104measured through the centerpoints of the corresponding end apertures106.

In a second preferred embodiment of the ring member 14, the innerdiameter is 7.480", the central diameter is 8.292", the radial thicknessis 0.812", the outer diameter is 9.104", and the thickness remains0.625". The ring member 14 similarly extends through an arc ofapproximately 280°. In that second embodiment, the two openings 104adjacent to the free ends each contain thirteen apertures orplaceholders, and the two intermediate openings 104 each contain sixteenapertures or placeholders, for a total of fifty-six apertures 106defining four openings 104. Each aperture 106 has a diameter ofapproximately 0.500", and the centerpoints of adjacent apertures 106 ineach opening 104 are spaced apart approximately 4°. Each opening 104 issimilarly spaced apart 12° from the adjacent openings 104 measuredthrough the centerpoints of the corresponding end apertures 106.

While the particular dimensions of these representative embodiments ofthe ring member 14 are provided purely for exemplary purposes in orderto facilitate an understanding of the relative proportions of the ringmember 14 compared to the bone 12 and anticipated working environment,and in particular the degree of freedom in selecting the optimalavailable placement and spacing for the elongated members 16 or wireholders 22 along the ring member 14, it may be readily appreciated thata wide variety of dimensions and tolerances may be selected for otherembodiments of the ring member 14 as dictated by the needs of theworking environment and the particular application, the stresses placedupon the ring member 14 in a particular application, as well as thedesires of the operator.

Clamping Assembly (20)

Referring to FIGS. 12 and 13, each clamping assembly 20 includes aU-shaped body 108 having a pair of parallel legs 110 each defining aradiused end and an aperture 112 extending therethrough, with a bridgesection 114 connecting the pair of legs 110 and defining a threadedaperture 116 through which a bolt 118 is received, the distal tip of thebolt 118 extending through the opposing face of the bridge section 114and into the region between the legs 110. The legs 110 are spaced apartslightly greater than the uniform thickness of the ring member 14 sothat the clamping assembly 20 is slidably mounted on the ring member 14to ride along the arc of the ring member 14 on the exterior side thereofto align the apertures 112 in the legs 110 with the apertures 106defining the openings 104. The distal tip of the bolt 118 contacts theexterior surface of the ring member 14 when the bolt 118 is tightenedwithin the threaded aperture 116. An elongated member 16 (or wire holder22) is inserted through the aperture 112 in one leg 110, through thedesired aperture 106 or placeholder in an opening 104 of the ring member14, and through the aperture 112 in the opposing leg 110. As the bolt118 is tightened into contact with the exterior surface of the ringmember 14, the bridge section 114 and legs 110 of the clamping assembly20 are pulled radially outward relative to the ring member 14 and intocontact with the elongated member 16 (or wire holder 22), which is inturn pressed radially outward into contact with the wall of the ringmember 14. The elongated member 16 (or wire holder 22) is therebysecurely fastened in position relative to the ring member 14 such thatthe elongated member 16 (or wire holder 22) cannot slide longitudinallyrelative to the ring member 14, and the elongated member 16 (or wireholder 22) remains at a fixed position along the arc of the ring member14 due to both the engaging contact and the undulating or curved innerwall of the opening 104 formed by the plurality of intersectingapertures 106.

Pin or Screw (24)

Referring particularly to FIGS. 14-17, a representative embodiment of apin or screw 24 used with the external fixation system 10 is shown, thescrew 24 having a generally cylindrical shaft 120, a proximal end 122defining a plurality of semi-hexagonal facets 124 designed to mate witha drill or manual tool for imparting rotation to the screw 24, a distalend 126 having a region of helical threads and a boring or cutting tip128 having four blades 130 designed to penetrate the bone 12 and form abore hole, clear debris from the bore hole, and pull the screw 24securely into the bone 12.

Lengthening-Compression-Distraction Bar (28)

Referring particularly to FIGS. 18-21, 27, and 28, a representativeembodiment of the lengthening-compression-distraction bar 28 (or "LCD"bar 28) is shown in detail. A first embodiment of the LCD bar 28 isshown in FIGS. 18 and 19, in which the LCD bar 28 includes a generallycylindrical central segment 132 having a pair of hollow, adjustablesleeve members 134 each disposed on opposing ends thereof, the open endsof each sleeve member 134 being sealed by a threaded end cap 136 fixedlyreceived within a threaded region of the bore extending through thesleeve member 134. Each end cap 136 defines a generally smoothcylindrical bore 138 through which a generally smooth region of acylindrical shaft 140 extends. The outward end of each shaft 140 has abolt head 142 fixedly threaded thereon, and the inward end of the shaft140 threadedly engages within the corresponding open end of the hollowcentral segment 132 which has an interior bore 144 which is similarlythreaded.

A pin 146 extends radially outward from an aperture defined by theexterior surface of the central segment 132 and is received within aslot or channel 148 defined by the adjustable sleeve member 134 toprevent the sleeve member 134 from rotating relative to the centralsegment 132.

In a second embodiment of the LCD bar 28 shown in FIGS. 27-29, athreaded nut 150 replaces the bolt head 142, with the threaded nut 150and the end cap 136 both being received on a corresponding threadedregion 152 extending longitudinally from and fixedly connected to theend of the central segment 132. In this second embodiment, theorientation of the pin 146 and slot 148 are reversed, so that the pin isfrictionally engaged in the sleeve 134 and extends into a slot 148defined in the central segment 132, a construction which increases thestrength of the embodiment. A washer 154 is disposed between the innersurface of the sleeve member 134 and confronting surface of the centralsegment 132 to facilitate rotation of the two components relative to oneanother without freezing or undue friction. The extending region 152further defines a generally smooth intermediate surface 156 againstwhich a hex screw 158 may be tightened to prevent rotation of the sleevemember 134 relative to the central segment 132, the hex screw 158 beingreceived within a transverse threaded aperture 160 extending entirelythrough the wall of the sleeve member 134. Referring to FIG. 29, the endof the extension region 152 defines a hex slot 162 depending axiallyinto the extension region 152 and aligned with the longitudinal axis,and designed to receive a hex key (not shown) of the same size as thatreceived by the hex screw 158. As may also be seen in FIG. 29, thethreaded nuts 150 have a generally bi-truncated cylindrical shapedefining a pair of opposing parallel sides.

In both embodiments of the LCD bar 28, the central segment 132 and thesleeve members 134 each have external cylindrical surfaces sized andshaped so as to be received within the C-shaped channel 36 of theextension finger members 18, so that one or more of the extension fingermembers 18 may be secured thereto in a similar manner as to an elongatedmember 16. Rotating the nut 142 or bolt 150 at the end of the LCD bar 28will move the corresponding adjustable sleeve member 134 and anyextension finger members 18 attached thereto longitudinally along theLCD bar 28 toward or away from its midpoint as shown in FIG. 20, tothereby place compressive or traction forces on the segments of bone 12to which the extension finger members 18 are connected via screws 24 orwire 26 as shown in FIG. 1 and the lower portion of FIG. 18.

In addition, the LCD bar 28 (referring to the second embodiment asexemplary) may be "dynamized" or adapted for dynamic compression (forexample, during the end stages of a fracture healing) by loosening boththe threaded nut 150 and the end cap 136 several millimeters, so thatthe sleeves 134 are free to "float" that small distance relative to thecentral segment 132 when weight or tension is placed on the affectedlimb or bone 12, while the fixation system 10 continues to constrain orprevent any twisting or torquing of the limb and bone 12.

The patient may also be instructed to perform periodic tensioning orcompression by placing the hex key into the hex screw 158, loosening thepressure exerted on the intermediate surface 156 of the extension region152 to permit rotation thereof, inserting the hex key into the axialslot 162 and rotating the central segment 132 to lengthen or shorten theLCD bar 28, and retighten the hex screw 158 against the intermediatesurface 156 to prevent inadvertent rotation of the central segment 132relative to the sleeve members 134.

As shown in FIG. 21, the components of the LCD bar 28 may also bereconfigured during fabrication for use in a transport mode, in whichthe cylindrical shaft 140 extends completely through or along thecentral member 132 (to a point disposed on the lower end in FIG. 21) andengages both bolt heads 142 (in the first embodiment) or threaded nuts150 (in the second embodiment), so that rotation in either the clockwiseor counter-clockwise directions will move the central segment 132longitudinally back and forth relative to the sleeve members 134,without affecting the longitudinal spacing between the sleeve members134 and the corresponding extension fingers 18 and screw pins 22attached to those sleeve members 134. In this manner, a section of thebone 12 may be secured to the central segment using one or moreextension fingers 18 and screw pins 24 (or wire 26), and "transported"longitudinally relative to the segments of the bone 12 secured to thesleeve members 134.

Wire Holder (22)

Referring to FIGS. 22-24, it may be seen that the wire holders 22 eachinclude a generally cylindrical body segment 164 having a radiused tip166 and defining a partially enclosed aperture 168 extendingtransversely therethrough. The body segment 164 defines a longitudinalbore 170 within which a plunger member 172 is slidably received, andwhich abuttingly contacts a threaded end cap 200 which is threadedlyreceived within the open end of the body segment 164 opposing theradiused tip 166. The plunger member 164 further defines a transverseaperture or concave surface 202 which may be aligned with the boundaryof the partially enclosed aperture 160 in the body segment 164, with theplunger member 172 being advanced into the body segment 164 bytightening the end cap 200 to securely pinch and hold any segment ofwire 26 or a screw pin 24 which is placed within the aperture 168. Theproper orientation of the plunger member 172 relative to the bodysegment 164 is similarly maintained using a pin 204 and slot 206assembly similar to that previously described above in reference toother components.

Rod Connector (174)

Referring to FIGS. 25 and 26, an additional component of the externalfixation system is shown for joining two or more elongated members 16 atvariable angles relative to one another, referred to herein as a rodconnector 174. One of the primary uses of the rod connector 174 is toassemble a half-hexagonal U-shaped fixation frame for the pelvis as isknown in the art, using three elongated members 16 joined by two rodconnectors 174. It is understood that the rod connector 174 may beemployed in other applications where two or more elongated members 16are joined at acute or obtuse angles relative to one another.

The rod connector 174 consists of a first open-ended U-collar 176 and asecond open-ended U-collar 178 stacked on top of each other, eachU-collar 176, 178 defining aligned a pair of apertures 180 through whicha bolt 182 is received to enclose the open ends of the both U-collars176, 178 and permit the U-collars 176, 178 to rotate about thelongitudinal axis of the bolt 182. The bolt 182 includes a faceted head184 and a threaded tip 186 which is received within a matingly threadedneck region 188 on the bottom or outer side of the second U-collar 178.Each U-collar includes a toothed or serrated face 190 which closelyconfront and contact one another when the bolt 182 is tightened into thethreaded neck region 188 to compress the U-collars 176, 178 toward oneother.

When the bolt 182 is tightened into the threaded neck region 188 tocompress the U-collars 176, 178 toward one other, the U-collars 176, 178deform sufficiently such that the opposing legs 192 of the U-collars176, 178 flex toward one another to reduce the inner diameter of thesemi-circular clamping surface 194, thus contacting and exertingpressure on the portions of the elongated members 16 received within thesemi-circular clamping surfaces 194 to secure and engage the elongatedmembers 16 against rotation or axial movement within the U-shapedcollars 176, 178. Angular movement of the elongated members 16 relativeto one another is similarly restrained by the effect of the matingserrated faces 190.

Referring again to FIG. 1, one exemplary configuration is depicted inwhich a ring 14 is fixed or secured relative to the proximal end of abone 12 by wires 26 extending from a plurality of wire holders 22mounted in the openings 104 of the ring 14 using clamp assemblies 20,and intermediate or distal portions of the bone 12 are fixed or securedby screw pins 24 mounted in extension finger assemblies 18 carried atthe ends of an elongated member 16 and LCD bar 28, respectively.

Referring to FIGS. 30 and 31, two other exemplary configurations aredepicted. In FIG. 30, a bone 12 is fixed or secured at opposing endsrelative to a single elongated member 16 using two pairs of extensionfinger assemblies 18 and screw pins 24, with the extension fingerassemblies 18 extending perpendicular from the elongated member 16 onopposing sides and at generally diverging obtuse angles relative to oneanother to present fixation sites from which the screw pins 24 mayextend into the bone 12 in a generally converging manner.

In FIG. 31, the opposing ends (or an end and an intermediate section) ofa bone 12 are fixed or secured relative to a pair of rings 14 which arespaced apart and maintained in generally parallel planar orientationmounted on a pair of LCD bars 28, the bone 12 being fixed using anappropriate combination of either wire 26 or screw pins 24. It may bereadily appreciated that the LCD bars 28 in FIG. 31 are in thelengthening-compression-distraction mode since no section of the bone 12is fixed or secured to the central segment 132 as would occur in thetransport mode.

The various components of the external fixation system 10 as describedherein may be fabricated from any suitable material known to the art foruse in such applications, including metallic or polymeric materialssuitable for use in biomedical applications and compatible with tissueto which the components will be exposed or contact, and selected asdictated by known or experimentally-determined parameters relating tothe suitable dimensions and mechanical stresses to which the componentswill be exposed during normal use as intended. The components may befinished or coated in any suitable manner using techniques known to theart to provide a workable and aesthetically pleasing surface, as well asto mitigate against certain deficiencies such as those caused by theexposure of certain metals or polymers to tissue or adverseenvironmental conditions. It may be appreciated that while a widevariety of known materials and finishes may be used, other materials ormanufacturing processes hereafter developed or discovered may also beutilized to achieve the particular benefits and advantages associatedwith those materials, finishes, or processes.

In operation, the external fixation system 10 is fabricated andassembled as described above, and provided to a physician or otheroperator for the purpose of fixedly securing or therapeuticallymanipulating one or more bones 12 of a patient, either during settingand healing of fractures or breaks in those bones 12, subsequent toreconstructive surgery, to provide for realignment or programmed growthof the bones 12, or for any other procedure to which the externalfixation system 10 may lend itself. The relevant components of theexternal fixation system 10 may be sterilized subsequent to manufactureand packaging, or prior to their use.

The various components of the external fixation system 10 may beassembled for a particular procedure in virtually any order or sequencewhich the operator finds convenient and practical to achieve theintended result, however it may be appreciated that for certain routineprocedures it may be suitable for the operator to have some componentsmounted together in a predetermined configuration to expedite their use,or to assist in visualizing placement of pins or screws 24 or wire 26relative to the bone 12 being acted upon.

Two steps in the method of using the external fixation system 10 whichwarrant particular note are the selection of the desired position forthe elongated members 16 or wire holders 22 along the ring member 14,and the one-handed engagement of the extension finger members 18relative to an elongated member 16 or the LCD bar 28.

Due to the intersecting apertures 106 defining the convoluted innerwalls of the openings 104, the elongated members 16 or wire holders 22may be spaced at closer adjacent intervals than if the apertures 106 didnot intersect (thus forming a greater plurality of discrete openings104), and greater control may be exercised over the radial positioningof the elongated members 16 or wire holders 22 which are spaced apart atnon-adjacent locations or placeholders along the arc of the ring member14.

Also as described above, once the extension finger member 18 is mountedon the elongated member 16 or LCD bar 28, the position and orientationof the screw 24 relative to the pin holder member 52--and the positionand orientation of the pin holder member 52 relative to the body member30 of the extension finger member 18--may be simultaneously clamped orsecured in a desired configuration with a one-hand motion by tighteningthe securing member 60 carried on the pin holder member 52, thusallowing the operator's other hand to hold, manipulate, or orient othercomponents of the external fixation system 10, the bone 12, or othertools or articles being utilized in the procedure.

While the preferred embodiments of the above external orthopedicfixation system 10 have been described in detail with reference to theattached drawings Figures, it is understood that the various depictionsof alternate embodiments and configurations are shown for exemplarypurposes only and do not limit the available applications orconfigurations in which the components of the external fixation system10 may be utilized, and further that various changes, modifications, andadaptations may be made in the external orthopedic fixation system 10without departing from the spirit and scope of the appended claims.

What is claimed is:
 1. In an external fixation system for aligning anelongated member in a longitudinal direction generally parallel with abone, said elongated member being mounted and secured in a desiredposition on a ring member, the improvement comprising:the elongatedmember having a central segment with a pair of opposing ends, a pair ofadjustment members each disposed on a corresponding one of said opposingends, and a pair of sleeve members each disposed on a corresponding oneof said pair of opposing ends, each of said pair of sleeve members beingmounted moveably longitudinally relative to said central segment whileconstrained against rotation relative to said central segment and oneanother, each of said pair of sleeve members being adapted for operableconnection to separate portions of the bone, such that rotation of atleast one adjustment member in a first direction will cause the pair ofsleeve members to move longitudinally relative to one another to exert atraction force upon the bone, and such that rotation of the at least oneadjustment member in a second direction opposing said first directionwill cause the pair of sleeve members to move longitudinally relative toone another to exert a compressive force upon the bone.
 2. Theimprovement of claim 1 wherein each of the pair of sleeve members isslidably mounted on the corresponding end of the central segment, thecentral segment defines a pair of threaded regions, and said adjustmentmembers comprise a pair of threaded end members each engagingly mountedon one of said pair of threaded regions and disposed at correspondingones of the pair of opposing ends, each of the pair of sleeve membersbeing operatively connected to a corresponding one of said pair ofthreaded end members, such that rotation of said pair of threadedregions relative to said pair of threaded end members will move the pairof sleeve members longitudinally relative to the central segment,thereby accomplishing a lengthening-compression-distraction mode for theexternal fixation system.
 3. The improvement of claim 2 wherein each ofthe threaded end members may be actuated to displace the pair of sleevemembers axially outward a small distance relative to the central segmentsuch that the pair of sleeve members may shift freely relative to thecentral segment through said small distance, whereby dynamization of theexternal fixation system may be accomplished by placing weight-bearingpressure on the bone which is absorbed by the bone through shifting ofthe pair of sleeve members relative to one another or to the centralsegment.
 4. The improvement of claim 1 wherein each of the pair ofsleeve members is slidably mounted on the corresponding end of thecentral segment and the sleeve members are separated by a spacingdistance, each of the pair of sleeve members being operatively connectedto one of the adjustment members such that rotation of at least one ofsaid adjustment members or the central segment moves the central segmentlongitudinally relative to the pair of sleeve members withoutsubstantially altering said spacing distance between the pair of sleevemembers, thereby accomplishing a transport mode for the externalfixation system.
 5. In an external fixation system for aligning a bone,the improvement comprising:an elongated member having a central segmentwith two opposing end portions; at least one adjustment member disposedon at least one of the opposing end portions; and at least two sleevemembers each disposed on a corresponding one of the two opposing endportions, the at least two sleeve members further being mounted moveablylongitudinally relative to the central segment and being adapted foroperative connection to a portion of the bone wherein rotation of the atleast one adjustment member causes at least one of the at least twosleeve members to move longitudinally relative to said central segmentand exert a force upon the bone.
 6. The improvement of claim 5 furtherincluding:a pin and a longitudinal slot associated with each of the atleast two sleeve members and the central segment, each pin extendingradially from one of the central segment and its associated sleevemember into its associated longitudinal slot, said longitudinal slotbeing formed in the other of the central segment and associated sleevemember.
 7. The improvement of claim 5 wherein the at least two sleevemembers are constrained against rotation relative to the centralsegment.
 8. The improvement of claim 5 wherein rotation of the at leastone adjustment member causes the at least two sleeve members to movelongitudinally to exert said force upon the bone.